#include "main.h"

#include "stm32l100c_discovery.h"

#include "ssd1306.h"

#include "config.h"

#include "eeprom_min.h"

// USB includes

#include "hw_config.h"

#include "usb_lib.h"

#include "usb_desc.h"

#include "usb_pwr.h"

#include "stringhelpers.h"

// TODO: Grab buttonpresses with interrupts

// USB Supporting Vars

extern __IO uint8_t Receive_Buffer[64];

extern __IO  uint32_t Receive_length ;

extern __IO  uint32_t length ;

uint8_t Send_Buffer[64];

uint32_t packet_sent=1;

uint32_t packet_receive=1;

// Globalish setting vars

uint8_t boottobrew = 0;

#define WINDUP_GUARD_GAIN 100

uint16_t windup_guard = WINDUP_GUARD_GAIN;

uint16_t k_p = 1;

uint16_t k_i = 1;

uint16_t k_d = 1;

// ISR ticks var TODO: Double check functionality after volatilazation... needed on ARM?

volatile uint32_t ticks = 0;

// Increase on each press, and increase at a fast rate after duration elapsed of continuously holding down... somehow...

uint32_t change_time_reset = 0;

#define CHANGE_PERIOD_MS 100

#define CHANGE_ELAPSED (ticks - change_time_reset) > CHANGE_PERIOD_MS

#define CHANGE_RESET change_time_reset = ticks

int16_t setpoint_brew = 0;

int16_t setpoint_steam = 0;

// State definition

enum state {

    STATE_IDLE = 0,

    STATE_SETP,

    STATE_SETI,

    STATE_SETD,

    STATE_SETWINDUP,

    STATE_SETBOOTTOBREW,

    STATE_PREHEAT_BREW,

    STATE_MAINTAIN_BREW,

    STATE_PREHEAT_STEAM,

    STATE_MAINTAIN_STEAM,

};

uint8_t state = STATE_IDLE;

static __IO uint32_t TimingDelay;

// Move to header file

void init_gpio();

void init_spi();

void process();

void machine();

void delay(__IO uint32_t nTime);

void restore_settings();

void save_settings();

void save_setpoints();

int main(void)

{

    // Init clocks

    SystemInit();

    // Init GPIO

    init_gpio();

    // Turn on power LED

    GPIO_SetBits(LED_POWER);

    // TODO: Awesome pwm of power LED (TIM4_CH4 or TIM11_CH1)

    // Configure 1ms SysTick (change if more temporal resolution needed) 

    RCC_ClocksTypeDef RCC_Clocks;

    RCC_GetClocksFreq(&RCC_Clocks);

    SysTick_Config(RCC_Clocks.HCLK_Frequency / 1000);

    // Init SPI busses

    init_spi();

    // Init OLED over SPI

    ssd1306_Init();

    ssd1306_clearscreen();

    // Check for problems on startup

    if(clock_fail) {

        ssd1306_DrawString("ERROR: Check Xtal", 3, 0);

        delay(2000);

    }

    // Startup screen 

    ssd1306_DrawString("therm v0.1", 1, 40);

    ssd1306_DrawString("protofusion.org/therm", 3, 0);

    delay(1500);

    ssd1306_clearscreen();

    restore_settings();

    if(boottobrew)

      state = STATE_PREHEAT_BREW; // Go to brew instead of idle if configured thusly

    GPIO_ResetBits(LED_STAT);

    // Main loop

    while(1)

    {

        // Process sensor inputs

        process();

        // Run state machine

        machine(); 

    }

}

// Read temperature and update global temp vars

int16_t temp = 0;

uint8_t temp_frac = 0;

void update_temp() {

    // Assert CS

    GPIO_ResetBits(MAX_CS);

    delay(1);

    // This may not clock at all... might need to send 16 bits first

    SPI_I2S_SendData(SPI2, 0xAAAA); // send dummy data

    //SPI_I2S_SendData(SPI2, 0xAA); // send dummy data

    uint16_t temp_pre = SPI_I2S_ReceiveData(SPI2);

    if(temp_pre & 0b0000000000000010) {

        ssd1306_DrawString("Fatal Error", 2, 35);

    }

    else if(temp_pre & 0b0000000000000001) {

        ssd1306_DrawString("Error: No TC", 2, 40);

        temp = 0;

        temp_frac = 0;

    }

    else 

    {

        uint8_t sign = temp >> 15;// top bit is sign

        temp_pre = temp_pre >> 2; // Drop 2 lowest bits

        temp_frac = temp_pre & 0b11; // get fractional part

        temp_frac *= 25; // each bit is .25 a degree, up to fixed point

        temp_pre = temp_pre >> 2; // Drop 2 fractional bits 

        if(sign) {

            temp = -temp_pre;

        }

        else {

            temp = temp_pre;

        }

    }

    // Deassert CS

    delay(1);

    GPIO_SetBits(MAX_CS);

}

// PID implementation

int16_t last_pid_temp = 0;

uint8_t last_pid_temp_frac = 0;

int16_t i_state = 0;

int16_t update_pid(uint16_t k_p, uint16_t k_i, uint16_t k_d, int16_t temp, uint8_t temp_frac, int16_t setpoint) 

{

  // Calculate instantaneous error

  int16_t error = (int16_t)setpoint - (int16_t)temp; // TODO: Use fixed point fraction

  // Proportional component

  int16_t p_term = k_p * error;

  // Error accumulator (integrator)

  i_state += error;

  // to prevent the iTerm getting huge despite lots of 

  //  error, we use a "windup guard" 

  // (this happens when the machine is first turned on and

  // it cant help be cold despite its best efforts)

  // not necessary, but this makes windup guard values 

  // relative to the current iGain

  int16_t windup_guard_res = WINDUP_GUARD_GAIN / k_i;  

  // Calculate integral term with windup guard 

  if (i_state > windup_guard_res) 

    i_state = windup_guard_res;

  else if (i_state < -windup_guard_res) 

    i_state = -windup_guard_res;

  int16_t i_term = k_i * i_state;

  // Calculate differential term (slope since last iteration)

  int16_t d_term = (k_d * (temp - last_pid_temp));

  // Save temperature for next iteration

  last_pid_temp = temp;

  last_pid_temp_frac = temp_frac;

  int16_t result = p_term + i_term - d_term;

  // Put out tenths of percent, 0-1000. 

  if(result > 1000)

    result = 1000;

  else if(result < -1000)

    result = -1000;

  // Return feedback

  return result;

}

uint32_t last_ssr_on = 0;

uint32_t last_led = 0;

int32_t setpoint = 0;

int16_t ssr_output = 0; // Duty cycle of ssr, 0 to SSR_PERIOD 

uint8_t pid_enabled = 0;

// Process things

void process()

{

    update_temp(); // Read MAX31855

    // TODO: Add calibration offset (linear)

    if(ticks - last_led > 400) 

    {

        GPIO_ToggleBits(LED_POWER);

        last_led = ticks;

    }

    // Every 200ms, set the SSR on unless output is 0

    if((ticks - last_ssr_on > SSR_PERIOD))

    {

        if(pid_enabled) 

        {

            // Get ssr output for next time

            int16_t power_percent = update_pid(k_p, k_i, k_d, temp, temp_frac, setpoint);

            //power-percent is 0-1000

            ssr_output = power_percent; //(((uint32_t)SSR_PERIOD * (uint32_t)10 * (uint32_t)100) * power_percent) / (uint32_t)1000000;

        }

        else 

        {

            ssr_output = 0;

        }

        // Only support heating (ssr_output > 0) right now

        if(ssr_output > 0) {

            char tempstr[6];

            itoa(ssr_output, tempstr);

            ssd1306_DrawString("#=", 2, 45);

            ssd1306_DrawString("    ", 2, 57);

            ssd1306_DrawString(tempstr, 2, 57);

            GPIO_SetBits(LED_STAT);

            GPIO_SetBits(SSR_PIN);

            last_ssr_on = ticks;

        }

    }

    // Kill SSR after elapsed period less than SSR_PERIOD 

    if(ticks - last_ssr_on > ssr_output || ssr_output == 0)

    {

        GPIO_ResetBits(LED_STAT);

        GPIO_ResetBits(SSR_PIN);

    }

}

void draw_setpoint() {

    char tempstr[3];

    itoa_fp(temp, temp_frac, tempstr);

    //ssd1306_DrawString("        ", 3, 40);

    ssd1306_DrawString(tempstr, 3, 40);

    ssd1306_DrawString("-> ", 3, 80);

    itoa(setpoint, tempstr);

    ssd1306_DrawString("    ", 3, 95);

    ssd1306_DrawString(tempstr, 3, 95);

}

uint8_t goto_mode = 2;

// State machine

uint8_t sw_btn_last = 0;

uint8_t sw_up_last = 0;